A semiconductor exposure apparatus for manufacturing a semiconductor device such as an LSI or a VLSI and a device manufacturing method using the same.
In a conventional laser process apparatus, e.g., a semiconductor exposure apparatus, the entire apparatus is covered with a chamber to allow temperature control of the apparatus and simultaneously ensure safety for operators of the apparatus and operators around the apparatus. Such a chamber of a laser process apparatus normally has a door through which an object such as a reticle to be exposed is loaded/unloaded into/from the apparatus. The laser is turned on only while the door is closed.
Normally, in such a semiconductor exposure apparatus, objects to be exposed are stored in a case capable of storing one or more objects to be exposed and loaded/unloaded into/from the apparatus. The semiconductor exposure apparatus incorporates a means for holding a plurality of cases, so not only a case that is currently being processed but also cases that are already processed or cases that are to be processed next can also be simultaneously held in the apparatus.
The semiconductor exposure apparatus has an interlock mechanism for protecting human bodies from being exposed to scattered light from a laser used as a light source or coming into contact with various manipulators.
The interlock is actuated instantaneously to interrupt laser oscillation and operation of manipulators when the work door of the chamber opens. Hence, when an operator carelessly opens the work door during a normal exposure sequence, the operation efficiency of the apparatus lowers. Interruption of laser operation adversely affects the quality of products.
When the operation of manipulators is interrupted, a long time is required to resume the exposure sequence. In the semiconductor exposure apparatus, to prevent such troubles, the lock of the work door is controlled in accordance with the state of the exposure sequence. The work door is originally provided on the chamber to load/unload wafer cassettes or reticle cassettes into/from the apparatus. Hence, the work door is controlled such that when no processing such as an exposure sequence is in progress, the work door is unlocked or the operator can easily unlock the work door, and when processing is in progress, the work door is locked.
In recent years, according to on-line or in-line automatization of a production system using an advanced semiconductor manufacturing apparatus, the operation efficiency of a semiconductor device manufacturing line is greatly increasing. In the manufacturing line, if troubles occur on the individual apparatuses, the entire production system stops. The frequency of various troubles that occur on the individual apparatuses and the time required for restoration largely influences the operation efficiency of the entire manufacturing line.
Under the circumstance, troubles due to human errors or malfunction of apparatuses are reduced by automation, improvement of apparatus performance, or improvement of maintenance technology. On the other hand, semiconductor exposure apparatuses have not taken sufficient measures against troubles on wafer conveyance due to wafer deformation in the semiconductor device manufacturing process. A wafer chuck error during wafer conveyance is representative of troubles due to wafer deformation. If a wafer chuck error takes place, the operator must interrupt the operation of the semiconductor exposure apparatus and remove the wafer while keeping the work door of the chamber open.
However, in the conventional semiconductor exposure apparatus, even when a wafer chuck error occurs during the exposure sequence, it is determined that processing in the apparatus is continued, and the work door of the chamber is kept locked.
To eliminate the error while keeping the work door of the chamber open, the work door must be forcibly unlocked using a dedicated key switch. When the work door is unlocked in this way, the lock is controlled without intervention of the sequence controller. For this reason, when the exposure sequence is resumed, a human error such as door open may occur. Depending on the state of the exposure sequence, opening the work door may adversely affect the quality of products or prolong the time required for restoration. Hence, to unlock and release the work door of the chamber to remove errors of this type, the operator must check the exposure sequence or unlock the work door of the chamber. This prolongs the time required for restoration and consequently lowers the operation efficiency of the entire manufacturing line.
The operation efficiency lowers, not only due to restoration for wafer conveyance errors, but also when the apparatus normally operates as a single unit for loading (supplying) or unloading (delivering) a case storing objects to be exposed into or from the apparatus. If cases can be loaded/unloaded only while the laser is not lasing, processed cases may stay loaded in the apparatus long after exposure or cases may have to wait long before loaded and exposed. In this case, the number of cases in process becomes large in the entire manufacturing line, and the manufacturing lead time of semiconductor devices increases.
During loading/unloading, every time the door is opened, the interlock for invalidating laser operation is actuated to ensure sufficient safety against the laser beam and disables laser operation. Hence, processing of the apparatus itself is interrupted.
Canceling the interlock and enabling laser operation require manual operation unlike the normal control sequence. However, if an xe2x80x9cerrorxe2x80x9d occurs due to manual operation, the operation efficiency of the apparatus further lowers because restoration for removing this error is individually required. An example of a human error will be described. The operator must close the door and then depress the laser oscillation start button. If the door is closed, and laser operation is resumed without depressing the button, the apparatus determines that the laser oscillation start button is not depressed and detects an error. The operator is not aware that the button has not been depressed until an error is detected. For restoration after this error, elimination of the error using control software of the apparatus, restoration of the hardware of the apparatus to the home position, and the like are necessary, resulting in a decrease in operationed efficiency of the apparatus. When the apparatus is incorporated in an in-line system, such error lowers the efficiency of the entire line.
The present invention has been made in consideration of the above situation, and has as its object to minimize the time necessary for restoration after a trouble such as a wafer chuck error which requires operator""s operation in the chamber of a semiconductor exposure apparatus so as to improve the operation efficiency of a manufacturing line as compared to the prior art.
It is another object of the present invention to allow to unload processed objects to be exposed (or cases storing the objects) or load objects to be exposed, which are to be processed, at an arbitrary time including the laser ON time and obviate the need for additional operations such as depressing a button every time objects to be exposed are loaded/unloaded into/from the apparatus, thereby preventing the operation efficiency of the apparatus from lowering due to loading/unloading the objects.
In order to achieve the above objects, according to the present invention, a semiconductor exposure apparatus and device manufacturing method using the exposure apparatus are characterized by the following arrangements.
There is provided a semiconductor exposure apparatus comprising determination means for determining a start or interruption of an exposure sequence, and control means for controlling to lock and unlock a door of a chamber of the semiconductor exposure apparatus in accordance with the determination result.
There is also provided a semiconductor exposure apparatus comprising means for determining whether or not an error generated during an exposure sequence can be eliminated by operation performed while keeping a door of a chamber of the semiconductor exposure apparatus open.
There is also provided a semiconductor exposure apparatus comprising means for detecting an error during a semiconductor exposure sequence, and means for determining the level of the detected error.
There is also provided a device manufacturing method using the exposure apparatus, comprising the steps of preparing the exposure apparatus, and performing exposure using the exposure apparatus.
There is also provided a semiconductor exposure apparatus comprising means for detecting an open/closed state of a door of a process chamber of the semiconductor exposure apparatus, means for controlling to lock the door on the basis of the detection result, and means for determining an interruption or resumption of a process in accordance with a locked/unlocked state of the door.
There is also provided a semiconductor exposure apparatus comprising scattered light limiting means for limiting the path where scattered light of a laser beam leaks from the apparatus in a plane or a space having a specific shape containing a path along which an object to be exposed or a case storing the object to be exposed moves, and loading/unloading means, engaging with the plane or space limited by the scattered light limiting means, for holding and moving the object to be exposed or the case while shielding the scattered light of the laser beam so as to load/unload the object to be exposed or the case between an internal space where the object to be exposed is irradiated with the laser beam and an external space.
There is also provided a device manufacturing method using the semiconductor exposure apparatus, comprising the steps of preparing the exposure apparatus, and performing exposure using the exposure apparatus.
According to a preferred aspect of the present invention, in the semiconductor exposure apparatus, the control means unlocks the door of the chamber when the exposure sequence is interrupted due to an error manufacturing.
According to a preferred aspect of the present invention, in the semiconductor exposure apparatus, the control means locks the door of the chamber when the interrupted exposure sequence is to be resumed.
According to a preferred aspect of the present invention, in the semiconductor exposure apparatus, the door of the chamber comprises a wafer cassette exchange door.
According to a preferred aspect of the present invention, in the semiconductor exposure apparatus, the door of the chamber comprises a reticle cassette exchange door.
According to a preferred aspect of the present invention, in the semiconductor exposure apparatus, unlock of the door of the semiconductor exposure apparatus is controlled on the basis of the determination result of the level of the detected error.
According to a preferred aspect of the present invention, in the semiconductor exposure apparatus, supply of a work to the semiconductor exposure apparatus is interrupted on the basis of the determination result of the level of the detected error.
According to a preferred aspect of the present invention, in the semiconductor exposure apparatus, the work comprises a wafer or a reticle.
According to a preferred aspect of the present invention, in the semiconductor exposure apparatus, when a work is being processed, the door is unlocked after processing of the work is ended.
According to a preferred aspect of the present invention, the semiconductor exposure apparatus further comprises unlock means for, on the basis of the determination result, interrupting the exposure sequence and then unlocking the door of the chamber of the semiconductor exposure apparatus, operation means for inputting an instruction for resuming the interrupted exposure sequence, and resumption means for locking the door and then resuming the exposure sequence.
According to a preferred aspect of the present invention, the semiconductor exposure apparatus further comprises notification means for notifying an operator that the door of the chamber of the semiconductor exposure apparatus is unlocked by the unlock means.
According to a preferred aspect of the present invention, in the semiconductor exposure apparatus, when an error is generated during wafer alignment or exposure processing, and the error does not adversely affect the processing, an interruption of the exposure sequence and unlock of the door by the unlock means are executed after exposure processing for all wafers is ended.
According to a preferred aspect of the present invention, a device manufacturing method using the exposure apparatus comprises the steps of preparing the exposure apparatus, and performing exposure using the exposure apparatus.
According to a preferred aspect of the present invention, in the semiconductor exposure apparatus, the object to be exposed comprises a reticle having a circuit pattern, and the object to be exposed is irradiated with the laser beam to transfer the circuit pattern to a photosensitive substrate.
Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof.